1. Field of the Invention
This invention relates to a self-cleaning filter for filtering fluids contaminated with debris and other contaminants. Specifically, this invention relates to a self-cleaning filter containing a movable filtering assembly which can be agitated during operation of the filter to automatically remove the debris and other contaminants that may accumulate on the filter assembly. The debris is collected and discharged from the filtering assembly and the clean, filtered fluids are discharged from the filter separate from the debris. The agitation of the filtering assembly permits rapid, continuous and easy removal of debris and other contaminants that operates independent of scraping or backwashing the filter assembly using pressurized water or air.
2. Description of Related Art
There are numerous occasions when fluids such as water and air must be filtered. One problem associated with every filtering system is that the filter inevitably will collect and accumulate debris and other contaminants present in the fluid, which, after a period of time, will prevent the filter from operating as intended. Many systems have been developed that serve to prevent the accumulation of debris on the filter surface.
It is well known to backwash filtering assemblies. But backwashing typically involves periodic down-time for the filtering assembly whereby forced water or air is directed against the filter in a direction opposite the direction of fluid flow to remove the accumulated debris. It also is known to employ a continuous back-washing system which solves one of the aforementioned problems in that the filtering apparatus need not be turned off as frequently. U.S. Pat. Nos. 5,192,429 and 4,822,486, describe continuous rotary self-cleaning filters that rotate about stationary nozzles (or stationary filters with rotating nozzles) whereby the nozzles direct spray against one side of the filter screen assembly in an attempt to force debris away from the other side of the filter screen assembly. These filter assemblies suffer from the drawback that the debris that is forced away from the screen assembly is not removed from the filter and therefore remains in the un-filtered water. After a period of time, the debris in the un-filtered water will become so concentrated that the filter will eventually become clogged and fail.
Other systems such as those disclosed in U.S. Pat. No. 3,622,006 have been developed whereby the filtering assembly is rotated and passes a collecting trough that includes an elongated mouth and lip that serve to scrape off debris that has accumulated on the filtering assembly. The debris that is scraped off then is drained away from the filter. The collecting trough and corresponding elongated mouth will eventually wear from the scraping action and will require replacement.
There are numerous other self-cleaning filtering assemblies that operate under similar principles whereby either a blade-type apparatus is used to scrape off the accumulated debris, or a forced water or air system is employed to back-wash the filtering assembly during its operation. The use of these extraneous mechanisms is expensive and difficult to fabricate and operate effectively. The design of many of the prior art self-cleaning filtering systems makes it quite difficult to replace the filter elements when different fluids are to be filtered or when a larger or smaller mesh filter is needed. These filters also will eventually wear or debris will become so concentrated in the filtering fluid that the filter will fail to operate.
Thus, there exists a need to develop a self-cleaning filtering system that is simple and easy to operate, and which makes it simple and easy to remove and replace the filter assembly. There also exists a need to develop a self-cleaning filter that does not involve an additional scraping mechanism or a forced water or air back-washing mechanism that forces the accumulated debris from the filter; thus, creating a self-cleaning filter that independently removes accumulated debris. There also exists a need to develop a self-cleaning filtering system which continuously filters a contaminated fluid, continuously removes debris and other contaminants from the filter that have accumulated on the filtering assembly, and that continuously removes clean filtered fluid from the filtering assembly.